1. Field of the Invention
This invention relates to a continuous process for efficiently transferring heat to a moving band of solid material.
2. Description of the Prior Art
The use of superheated vapor for drying articles and for heat fixing dyes in synthetic polymers is well known. For example, Belgian Pat. No. 760,243 discloses the use of recycled heavier-than-air superheated solvent vapors for fixing dyes, particularly those applied to fabrics from organic solvents. The preferred organic solvents are the chlorinated hydrocarbons, especially the aliphatic chlorocarbons having boiling points of 80.degree. - 150.degree. C. German Publication No. 2,161,733 discloses the use of superheated vapors of 1,1,2-trichloro-1,2,2-trifluoroethane or trichlorofluoromethane for drying articles which are wet therewith. U.S. Pat. No. 3,762,872 discloses the simultaneous drying and heat fixing of dyes on textiles using the superheated vapors of various chlorocarbons, chlorofluorocarbons or fluorocarbons. U.S. Pat. No. 3,542,506 discloses the use of superheated steam, moving in a countercurrent direction, for sweeping organic vapors from a band of material containing same. Thereafter, the steam and the organic vapors are condensed, the water layer is discarded, and the organic layer is recovered. Finally, it is known to exclude non-condensable gases, such as air, from enclosures for treating textiles with organic vapors in order to facilitate condensation of the vapors.
In general, the prior art textile treating processes usually provide practical rates of heat transfer only if the superheated vapors pass over the fabric at an accelerated rate. Blowers and other means are employed to achieve rapid circulation.